User blog:Hurricane Layten/Dangerous tornado outbreak possible next week
OK, this one might take some time, but here it goes. Model runs are suggesting a potent midway trough will be present across the four corner states. It is worth noting that although the Euro and GFS models, whilst showing different intensities of the trough and locations, both show a very moist environment over the four corners states of TX, OK,NE and AR. The Euro is particularly consistent with this scenario, ejecting a vigorous shortwave trough from the central plains states. The GFS, on the other hand, keeps the trough going into the the four corners states. Both models, however, collide a very moist airmass with a well developed dryline by the afternoon of Thursday, April 28, and besides the difference between the modelling solutions, both models move a mid-level jet stream through this warm sector, allowing the jet to strengthen as it moves into the early evening. The SPC is calling for a high-end severe weather threat, but are hesitant to issue a High Risk so far in advance, but I'm certainly saying there will be at least a Moderate, maybe even a High Risk, from this event. The SPC is calling for the potential for large to very large hail, significant damaging damaging winds, and even more concerning so far in advance, tornadoes. On April 29th, the SPC is again calling for a high end severe weather event, which to me looks like a Moderate Risk event at this time. Again, the models are calling for another upper level trough to move through the four corners region again, with another very moist environment, this time over the southern plains. A surge of moisture is expected in the northern areas of the southern plains. One thing can be said at this point, and that is that a high end severe weather even is again possible on this day, with the potential for supercells, large hail, damaging winds, and again, tornadoes. Although no risk area is mentioned at this time, there is the potential for severe weather from this series of troughs on Days 4, 5 and 8, but there is considerable uncertainty in the model solutions for any exact areas to be named as of this time. I will definitely be keeping an eye on this situation as it develops, as it will be life threatening if it does actually materialise. Updates April 23, 2017 A Slight (15%) Risk contour area is now present for the Day 4, 5, and 7 outlooks. An Enhanced (30%) Risk area is now present for the Day 6 areas, and a "higher end" significant severe weather event is still expected in the areas mentioned yesterday. OK, above is the recent GFS model soundings for central OK on April 28th. this was initialised at 0000 UTC. For those of you thta cant read the sounding, I will rub you through it now.The "poss haz type" is self explainatory, and is calling for a "PDS TOR", which basically means a PDS tornado event. What is also shown on this sounding is that there is a 50.8% chance for supercell development in this region, and also the potential for significant hail. Though the significant supercell section is empty (this requires a 3 day outlook), I'm sure that this will change over the coming days. Looking at the sounding, th GFS seems to be hinting at a very moist environment, with a maximum shear value of 64 kt, which again, is favourable tornadoes. Even more concerning, down the bottom right side of the sounding is the tornado potential. The EF4+ section in particular is of concern, which calls forbetween a 30% and a 80% chance of EF4+ tornadoes, with an average of just over 50%. This basically means thta some model runs have a high potential for EF4+ tornadoes, whilst others have a low potential. This has been cancelled out to give the 50% median probability. Also on this sounding is a 93% chance for significant hail, and a 67% chance for tornadoes, which I've never seen before. The GFS is now in its season for being reliable, so I am concerned for the event that is being predicted. The CAPE values are expected to be 5086 J/kg3, which if comes to light, is darn well rediculously high, and very favourable for a significant tornado outbreak across parts of OK, TX and AR. I will be keeping an ye on this, as it will likely become a dangerous tornado outbreak.